Draft regulator



Dec. 30, 1947. HELD, JR 2,433,749

DRAFT REGULATOR Filed Dec. 20, 1945 2 Sheets-Sheet 1 X 59 /0 824 27/ z;z 2a@ y/ fi'yii INVENTOR.

Fda/ardAFZ'e/dcfi? ATTORMEY Dec. 30, 1947. E. A. FIELD, JR 2,433,749

DRAFT REGULATOR Filed Dec. 20, 1945 2 Sheets-Sheet 2 INKENTOR. 7 2210c7/1 '4 TTORNEVO',

Patented Dec. 30, 1941 UNITED STATES PATENT OFFICE DRAFT REGULATOREdward A. Field, Jr., Mendota, 111. Application December 20, 1943,Serial No. 514,895

1'1 Claims. 1

This invention relates to improvements in draft regulators.

The main objects of this invention are:

First, to provide an improved draft regulator for heaters and the likeadapted to be attached to the smoke flue thereof to control the heaterdraft, said regulator having features of construction rendering the sameextremely sensitive in operation as well as economical of production.

Second, to provide aregulator or draft control of the type describedhaving means of adjustment particularly adapting the regulator for thedraft conditions of a horizontal fiue as Well as for those of a verticalflue.

Third, to provide a draft regulator of the type described including acounterweighted gate in which the counterweight may be adjusted to andfrom the axis of the gate in'two different planes, in one plane when theregulator is connected to a horizontal flue and in the other plane whenconnected to a vertical flue.

Fourth, to provide a control of the type described including a controlgate of a special shape to provide extra turning thrust on the front ofthe gate to overcome some of the thrusts due to eddy currents at theback thereof,

Fifth, to provide a draft control of the type described including a gatehaving an improved hinge structure to reduce friction to a minimum, andthat functions in an eifective and silent manner.

Objects relating to details and economies of the invention will appearfrom the description to follow. The invention is defined in the claims.

A preferred embodiment of the invention is illustrated in theaccompanying drawings, wherein:

Fig. 1 is a front elevational view of the draft regulator.

Fig. 2 is a fragmentary view in side elevation partially broken away andin section on line 2-2 of Fig. 1, illustrating various details andstructural relationships of the parts.

Fig. 3 is a section on line 33 of Fig. 1 illustrating the gate and thering frame support therefor.

Fig. 4 is a fragmentary view in section on line Fig. 7 is an enlargedfragmentary view in section on line 1-1 of Fig. 3 illustrating thedetails of the hinge connection of the gate to its annular supportingframe.

Fig. 8 is an enlarged fragmentary sectional view corresponding to thesection of Fig. 2, en-

Fig. 1 illustrating the counterweight means for producing closing torqueon the control gate.

Fig. 10 is a diagrammatic illustration of the control gate and therelative angular positions of the center of gravity of the counterweightfor producing closing torque on said gate, in the open and closedpositions of said gate.

The invention herein disclosed embodies in part modifications of certainof the features of construction of the draft regulator disclosed in mycopending application, Serial No. 453,401, filed August 3, 1942, forDraft regulator, particularly adapting the regulator of the type thereindisclosed to be readily adjusted to the draft conditions of either ahorizontal or a vertical flue, as hereinafter described in detail.mentioned application matured April 18, 1944, into Patent No. 2,346,740.

In accordance with the present invention'there is provided an improveddraft control or regulator of the counterweighted gate type, saidregulator being attached to a smoke flue I of any type of heater unit(not shown), such as a space heater, stove, furnace, or the like. Theflue may be horizontally disposed or vertically disposed as shown inFig. 2. In the illustrated embodiment the regulator comprises acylindrical sheet metal housing 2 adapted to fit against the side of theflue l and secured thereto by any suitable means well known to the art.

At its outer end the housing 2 telescopically receives an annularstamped sheet metal rim or gate frame 3 provided with a radiallyout-turned flange 4 abutting the outer end of the housing 2. A screw 5has threaded engagement within an opening in an integral radiallyinwardly offset portion 6 of the rim 3 and engages the inner surface ofthe housing 2 so as to secure the rim or gate frame 3 within the housing2. In actual practice the frame 3 is desirably stamped from a singlesheet metal disk to the sharply dished outline as shown in Figs. 2 and3, following which the thus conformed member has a gate blank punchedfrom the inner portion thereof in the desired outlineof the swingablegate 1 of the control. This procedure greatly simplifies and expeditesthe operation of forming the gate and The above effects a considerablesaving of material, and simultaneously results in the formation of thegate opening in the gate frame 3. Following the blanking out of the gateblank the latter is dished inwardly at 8, as illustrated particularly inFigs. 2 and 3, to give rigidity to the gate and to allow for a slightclearance between the outer edge of the gate and. the inner edge of thegate frame.

The gate 1 is provided with a pivoting hinge pin in a simple andinexpensive manner by dis-' posing an elongated wire rod or pin element9 on the outer or forward side thereof and passing said pin throughopenings formed in the inclined annular dished or flange portion 8 ofthe gate on opposite sides of the latter. This hinge pin is disposedccentrically of the gate and. somewhat below the center of mass of thelatter.

At opposite sides of the gate frame 3, I mount hinge brackets l0, thesebrackets having platelike attaching portions spot-welded or otherwisesuitably secured to the gate frame 3. The brackets have rearwardly orinwardly turned arms ll having slots l2 therein, the lower edges ofwhich rollingly receive the ends of the hinge pin 9, to afford a silentand substantially frictionless hinge support for the gate 1. It will benoted that the bearing surfaces of the slots l2 are inclined upwardly inthe arc of a circle commencing at the front of the slot and extending-tothe rear thereof. By thus inclining the bearing surfaces, the hinge pin9 is prevented from skidding backwards against the rear ends of theslots, causedv by pressure of the air against the front of the gate. Ifthis skidding happens the hinge pin will no longer roll in the slots butmust turn against the rear ends of the slots as in an ordinary bearing.By inclining the bearing surfaces of the slots l2 in the arc of a circleso that the angle of inclination slightly increases from the front endof the bearing surface to the rear end thereof, as shown in Fig. '7, thehinge pin will soon find a place on the bearing surface inclined at anangle of 2 or 3 degrees for ordinary drafts to ,4 or 5 degrees for verystrong drafts, where it will rollingly engage said bearing surfacewithout skidding in the event that the control is not installed exactlyon the level, thereby facilitating ease and rapidity in installing thecontrols. It will be noted by reference toFig. '7 that the radius ofcurvature of the bearing surface of the slot I2 is relatively large ascompared to the radius of curvature of the bearing surface of the pin 9.This permits the pin to roll rearwardly during opening of the gate' froma closed vertical position to widely opened substantially horizontalposition without the pin engaging a too steep an incline such as willcause the pin to slide or skid down the incline and prevent free rollingcontact of the pin with the bearing surface of the slot. To preventendwise movement of the hinge pin 9 in its bearing slots l2, lugs l3 arebent rearwardly from the gate frame 3 to engage the ends of the pin.

Referring to Figs. 1 and 2, it will be noted that the gate frame 3 has aconsiderable segment of the material of which it is fabricated,designated ll, left therein at the lower portion thereof, instead ofblanking this material out as a part of the gate. The purpose of this isto provide a large area of the gate above the hinge pin 9 thereof, ascompared to the gate area below the hinge pin. The force tending to openthe gate is only equal to the pressure of the air acting upon thedifierential in the area between said upper and lower areas. I haveaccordingly pmvided a relatively large differential, as compared to thesize of the gate itself, so that a given air pressure acting on the gateswings the same with sufficient force to overcome any factor tending tocause sticking of the gate, for example, accumulation of dirt or soot atthe hinge thereof. With the upper half of the gate of a generallycircular outline as shown so as to closely fitthe circular housing andprovide for a gate of maximum area, it is essential that the hinge pin 9extend through the housing closely adjacent the axis of the circularhousing in order to prevent the circular edges of the gate striking thehousing when the gate opens.

In order to limit the movement of the gate between its open and closedpositions, I provide a 'stop member for the open position consisting ofa relatively elongated spring stop lug or member l5 struck radiallyinwardly from one side of the gate frame 3. This stop coacts with thegate 1 in the manner clearly illustrated in Fig. 2, in the fully openedposition of the gate. In order to limit the movement of the gate in theopposite direction or closed position I provide a closing stop I6 in theform of a relatively long finger formed on the plate I! as hereafterdescribed. This finger engages the gate frame 3 as shown in Figs. 1 and3 to limit the closing movement of the gate. To lock the hinge pin 9 tothe gate, the plate I! is provided with a projecting portion l8 engagingover the hinge pin. A bolt l9 passes through an opening in theprojection l8 and an opening 20 in the gate 1 and is provided with a nut(not shown) at the back of the gate for drawing the parts into tightengagement.

As the hinge pin 9 of the gate is set off center it is necessary thatthe gate have a balancing means to adjust the differences in weightabove and below the hinge pin, so counterweights or balance weights 2iand 22 are provided. The balance weights 2| consists of a heavy piece ofmaterial shaped more or less like the plate I! which covers the samewhen the parts are fully assembled. The cover plate I! and the balanceweights 2| are secured to the front of the gate by the attaching rivets23 and 24 extending through openings 25 and 26 respectively in the gate.The balance weight 22 is mounted on the inner side of the gate and issecured thereto by the single attaching rivet 23 extending through saidweight eccentric thereof. The sole purpose of the weight 22 isto enablethe gate to be properly balanced prior to leaving the factory.Thereafter it is not designed'to be manipulated in any manner.

Another counterweight means is also provided which providesfor the soleclosing torque of the gate. This counterweight means has two separateadjustments, one being for controlling the draft and the other adaptingthe draft control for the draft conditions of either a vertical or ahorizontal flue. The counterweight for this means comprises thewasher-like weights 2'! and the weight adjustment arm or lever 28. Theweights 21 are mounted upon the arm or lever 28 by means of a tubularrivet or eyelet 29 which is inserted through the weights, one beingdisposd on either side of the arm and between the arms of the lever atthe bight thereof. This eyelet or rivet is headed at one end and offsetat the other as'shown in Fig. 9 for retaining the washer-like weights.The bolt 30 with its nut 30! inserted through the eyelet suppliesadditional weight and is used when the mechanism is set for operation ina horizontal fine. For

horizontal pipe installation the weight washers 21 and securing bolt 38are installed on the eyelet 29 on weight arm 28, but for vertical pipeinstallation the bolt is omitted, the weight arm 28 alone then providingclosing torque for such vertical flue installation. The weight arm 28has at the end or one arm thereof an inwardly bent portion 3| pivotallymounted between the opposite offset portions 32 in the supporting lever33 pivotally mounted on the hinge pin 9 and projecting through avertically elongated opening 34 in the gate 1 and to the rear of thegate so that the enlarged portion 35 of the supporting arm at the rearof the hinge pin counterbalances the portion of the arm forward of thehinge pin. The weight arm 33 at its forward end is provided with arearwardly bent extension 38 with its forward portion of quadrant shapeand with its rearward end pivoted on the hinge pin 9 and projectingtherebeyond through an opening 31 in the gate 1. The weight arm 28clampingly embraces the quadrant of the arm extension 36, so that theweight arm 28 may be retained in any adjusted position to provide forthe draft control desired. To further insure the weight arm 28 beingretained in adjusted position the quadrant 28 is provided with notches38 appropriately designated as high, medium and low, as shown in Fig. 1.The pivot 3| of the weight arm 28 is so disposed relative to thesupporting lever or arm 33 that the arm 28 with the weights 2! thereonis adjusted toward and from the hinge pin 9 and in a plane having lyingtherein the pivotal axis of the gate. 1

The weight arm 28 with the weights 2! thereon may be adjusted to swingin either of two planes, both of which have lying therein the pivotalaxis of the gate, these planes of adjustment being disposed at"difierent angular distances from the plane of the gate to provide, fordifferent closing torques on the gate. When the draft control isinstalled on a vertical flue, to provide a greater closing torque on thegate in the closed position thereof and a smaller closing torque in thewidely opened position thereof, as compared to the closing torques onthe gate for the corresponding positions respectively of the gate forhorizontal pipe installation, the plane of adjustment of the weight arm28 is at a greater angular distance from the plane of the gate than whenthe draft control is connected to a horizontal flue, for the reason thatwhen connected to a vertical flue the smoke eddying into the collar ofthe draft control strikes the back of the gate with greater force andoffers greater resistance to the opening of the gate than when the draftcontrol is connected to a horizontal flue.

The means for effecting this adjustment comprises an outwardly andupwardly projectin curved arm 39 integral with the plate I1 and providedwith an inner lower opening 48 and an outer upper opening 4|, both ofwhich are adapted to receive a screw 42 having threaded engagement in anopening in the supporting lever 33 to which the weight arm 28 ispivoted. When installing the draft control to a vertical flue the screw42 is inserted through the upper opening 4| and threaded into the lever33, a shown in Fig. 4,thls without the use of the bolt 30, providing forthe necessary closing torque on the gate 1 when the control is connectedon the vertical flue. When installing the draft control on a horizontalflue, the screw 42 is inserted in the lower opening 40 and this,together with the bolt 30 provides for the additional closing torquenecessary when the control is installed on a horizontal flue. It will benoted that whether the supporting lever 33 i connected at the upperopening 4| for the torque necessary when the draft regulator isconnected to a vertical flue or is connected to lower opening 48 for thetorque necessary when the draft regulator is connected to a horizontalflue, in both instances the adjustment. of weight arm 28.relative to thequadrant position of the arm 38 for low, medium draft control remainsthe same.

During the assembly operation at the factory all the'parts are mountedon the gate, with the exception of the weights 21 and their supportingarm 28. Without this arm and these weights, but with all the otherparts, the gate is designed to be nearly in balance-that is, the centerof gravity is located on the center line of the hinge pin 9, theflnalbalancing having been eifected by adjustment of the eccentricallymounted balance weight 22 about th rivet 23. The weight arm 28 providesthe closing torque, this torque being slight if the arm is set in anotch 38 desi nated as low draft, and greater if the lever is adjustedoutwardly to a notch 38 designated as high draft. As the weight arm 28is adjusted outwardly the center of gravity of said parts also movesoutwardly which increases the moment of force tending to close the gate.If the supporting lever 33 is attached at the outer hole 4|, forvertical pipe installation, as the gate opens, the center of gravity ofthe torque arm moves outward and upward for the first 25 degrees, andthen inward and upwardfor the next 50 degrees, as shown in thediagrammaticillustration of Fig. 10. If the supporting lever 33 isconnected at the inner hole 48, for horizontal pipe installation, saidcenter of gravity moves outward and upward for the first 5'7 degrees andthen inward and upward for the next 18 degrees. Because of the abovementioned inward and upward movement of 50 degrees when adjustment imade for a vertical flue installation, as compared to inward and upwardmovement of only 18 degrees when adjustment is made for a horizontalflue installation, resulting in the closing torque on the gate duringthe latter part of its opening movement decreasing a considerably andrelatively rapidly in vertical flue installation, as compared to that ofa horizontal flue installation, it is desirable that the opening thruston the gate be increased in substantial opened positions thereof tooffset he above mentioned varying conditions. This 1 creased thrust iseffected by bending a substantial segment of the upper portion of thegate 1 outwardly at an angle of approximately 20 degrees to the plane ofthe gate as shown at 43 in Fig. 2. This, in addition to the flange orangle resulting from the dishing of the gate, provides a substantialflange against which the air flowing over the gate impinges, even whenthe gate is in its fully open position as shown in Fig. 2. This not onlyincreases the 'opening thrust against the gate, particularly the gate,and gives desirable results for both vertical and horizontalinstallations of the draft regulator.

The above described control may be quickly and accurately adjusted foreither vertical or 7 horizontal flue installations. It is very easily,quickly and economically manufactured. There are no parts requiringconsiderable attention and care in use, and it is exceedingly sensitiveand accurate in operation.

I have illustrated-and described my invention in an embodiment which Ihave found very practical. I have not attempted to illustrate ordescribe other embodiments or adaptations as it is believed thisdisclosure will enable those skilled in the .art to embody or adapt myinvention as may be desired.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a draft regulator, a cylindrical open ended control housing, acircular gate frame disposed concentrically adjacent the open end of thehousing, a controlgate of generally circular outline pivoted on saidgate frame, the pivotal axis of said gate being horizontal and extendingrelatively close to the axis of the circular housing, the periphery ofsaid gate being disposed closely adjacent said gate frame and the gatebeing truncated on a chord parallel to the gate axis to thereby afford alarge pressure area differential on opposite vertical sides of saidaxis, said gate having an outwardly inclined portion along the upperedge thereof to increase the opening thrust on the upper portion of saidgate in relatively wide open positions thereof, a weight arm and aweight thereon together constituting a counterweight to produce closingtorque on said gate, a pivotally adjustable lever, the pivotal axis ofsaid lever and the pivotal axis of the gate coinciding, said leverextending outwardly and downwardly from said gate to swing to and fromthe gate, said weight arm being pivoted to said lever to swing to andfrom the pivotal axis of the gate and to swing in a plane having thepivotal axis of the gate lying therein, means for retaining the weightarm with the weight thereon in different adjusted angular positionsrelative to the said lever to adjust the draft control, and

means for retaining said lever in different adjusted angular positionsrelative to said gate to adapt the regulator for the draft conditions ofeither a horizontal or a verticaiflue.

2. In a draft regulator, a cylindrical open ended control housing, acircular gate frame disposed concentrically adjacent the open end ofsaid housing, a control gate of generally circular outline disposed insaid gate frame, a hinge pin horizontally disposed on said gate andfixedly. secured thereo, bearing members having bearing surfacesupwardly curved in a rearward direction for rollingly supporting theopposite ends of said hinge pin, the lower portion of said gate beingtruncated on a chord parallel to said axis to provide a large pressurearea differential on opposite vertical sides to the axis of the gate,the upper edge portion of the gate being inclined outwardly at an angleof approximately 20 de-- adjusted angular positions relative to saidleverfor varying the draft, and means for retaining I said lever indiiferent adjusted angular positions 8. In a draft regulator, a circularopen ended control housing for passage of air therethrough to a smokeflue, a gate of generally circular outline in said housing forcontrolling the passage of air therethrough, said gate being mounted ona horizontal axis disposed closely adjacent the center of said housing,said gate having differential pressure areas above and below said axisto open said gate by excess of pressure on the outer surface thereof, acounterweight for prolucing closing torque on said gate, a leverpivotally mounted to swing about an axis substantially coincident withthe horizontal axis of the gate to and from the plane of the gate, saidcounterweight being pivotally mounted on said lever to swing to and fromthe horizontal axis of the gate and to swing in a plane coincidingsubstantially with said axis, means for retaining said counterweight inpivotally adjusted positions on said lever for adjusting the draftcontrol, and means for retaining the lever in adjusted angular positionsrelative to the plane of the gate to adapt the regulator for the draftconditions of either a horizontal or a vertical flue.

4. In a draft regulator, anopen ended control housing for passage of airtherethrough to a smoke flue, a control gate for the housing, said gatebeing pivotally mounted on a horizontal axis and having differentialpressure areas above and below said axis, the area above beingsubstantially greater than that below, counterweight means includinganarm for producing a closing torque on said gate, a lever pivotallymounted on said gate to swing to and from the plane of the gate, saidarm being pivotally mounted on said lever to swing to and from the axisof the gate and to swing in a planeooinciding substantially with saidaxis, means for retaining the arm in pivotally adjusted positionsrelative to the lever, and means for retaining the lever in pivotallyadjusted positions relative to the gate.

5. A draft regulator device comprising an open ended control housing forpassage of air therethrough into a flue, a control gate horizontallypivotally mounted in said housing, counterweight means including an armto produce a closing torque-on said gate, a lever pivotally mounted onthe gate to swing to and from the plane of the gate, the pivotal axis ofsaid lever substantially coinciding with the pivotal axis of said gate,means for retaining said lever in different angular positions relativeto the plane of the gate, said arm being pivotally mounted on said leverto swing to and from the pivotal axis of the gate and in a plane havingsubstantially lying therein the pivotal axis of the gate, and means forretaining said arm in different angular positions relative to saidlever.

6. A draft regulator device comprising an open ended control housing, acontrol gate disposed adjacent the outer end of said housing andpivotally mounted on a horizontal axis, a counterweight for producingclosing torque on said gate,

the pivotal axis of the gate and in a plane having lying substantiallytherein the pivotal axis of the gate.

7. A draft regulator device comprising an open ended control housing, acontrol gate disposed adjacent the outer end of said housing and mountedon a horizontal axis, a counterweight for producing closing torque onsaid gate, a first means on said gate for adjusting the counterweight toand from the plane of the gate to adapt the draft regulator for thedraft conditions of either a vertical or a horizontal flue, a secondmeans adiustable on said first means for moving the counterweight to andfrom said horizontal axis for adjusting the draft when the draft reulator is connected to either a vertical or a horizontal flue, saidsecond means including a lever pivoted to said first means, the pivotalaxis of said lever extendin in a direction substantially at ri ht anglesto the direction of said horizontal axis of said gate.

8. A draft regulator device comprising an open ended control housing, acontrol gate disposed adjacent the outer end of said housing and mountedon a horizontal axis, counterweight means for producing closing torqueon said gate, a lever pivotally .adjustably mounted on said gate. thepivotalaxes of the lever and gate substantially coinciding, the leverprojecting on opposite sides of its pivotal axis and through the gate tothe opposite sides thereof and having its opposite ends on oppositesides of its pivotal axis substantially balanced, said counterweightmeans mounted on the lever for adiustment towards and from the pivotalaxis of the gate; and for adjustment in a plane coinciding substantiallywith the pivotal axis of the gate.

9. In a draft regulator. an open ended control housing for passage ofair therethrough into a flue, a pivoted control gate disposed adiacentthe outer open end of said housing and adapted to be opened by excesspressure on the outer surface thereof. a first means for producing aclosing torque on said gate, a second means for adjusting said firstmeans to adjust the closing torcue to adapt the draft regulator to thedraft conditions of either a vertical or a horizontal flue, and a thirdmeans for adjusting said first means to adjust the closing torque tovary the draft when the regulator is connected to either a vertical or ahorizontal flue, said second and third means including two leverspivotally adjustably connected to each other, one of said levers beingpivotally adjustably connected to said gate, and the other lever suporting said first means, the pivotal axes of the two levers i extendingin directions substantially at right angles to each other, the lastnamed lever swinging on its pivotal connection with the first-namedlever in a plane substantially parallel and substantially coincidingwith the axis of the pivotal connection of the first-named lever to thegates 10. In a draft regulator device, an open ended control housing forpassa e of air therethrough into a flue, a pivoted control gate in theouter open end of said housing to be opened by excess of pressure on theouter surface of the gate, counterweight means on said gate forproducing a closing torque on said gate, a horizontally disposed hingepin to which said gate is fixedly secured, bearing members at theopposite ends of said pivot pin; said bearing members'having bearingsurfaces upwardly curved in a rearward direction for rollinglysupporting said pivot pin,

the bearing surfaces of said pin being curved and providing acontinuously and uninterruptedly curved rolling contact with theupwardly curved bearing surfaces of said bearing members during movementof the gate from a closed substantially vertical position to a widelyopened substantially horizontal position, the radius of curvature of thebearing surfaces of the bearing members being relatively large ascompared to the radi s of curvature of the bearing surfaces of said p n,the rearwardly and upwardly curved bearing surfaces of the bearingmembers being adapted progressively to increase gravitational resistanceto the opening of said gate as said pin rolls rearwardly and upwardlyalong the progressively increasing steepness of said curved bearingsurfaces, the gravitational resistance being at a minimum when the pinis in a forward position.

11. A draft regulator device comprising an open ended control housingfor passage of air therethrough into a flue, a control gate horizontallypivotally mounted in said housing to be opened by excess of pressure onthe outer surface thereof, means for producing a closing torque on saidgate, hinge means on said gate, and bearing members having bearingsurfaces upwardly curved in a rearward direction for rollinglysupporting said hinge means, the bearing surfaces'of said hinge meansbeing curved and providing a continuously uninterruptedly curved rollingcontact with the upwardly curved bearing surfaces of said bearingmembers during movement of the gate from a closed substantially verticalposition to a widely open substantially horizontal position, the radiusof curvature of the bearing surfaces of the bearing members beingrelatively large as compared to the radius of curvature of the bearingsurfaces of the hinge means, the rearwardly and upwardly curved bearingsurfaces of the bearing members being adapted progressively to increasegravitational resistance to the opening of said gate as said hinge meansroll rearwardly and upwardly along the progressively increasingsteepness of said curved bearing surfaces, the gravitational resistancebeing at a minimum when the hinge means is in a forward position.

12. A draft regulator device comprising an open ended control housingfor passage of air therethrough to a flue, a control gate horizontallypivotally mounted in the outer open end f said housing to be opened byexcess of pressure on the outer surface thereof, a first leverconstituting a counterweight to produce a closing torque on said gate, asecond lever mounted for angular adjustment about the pivotal axis ofsaid gate to and from the plane of the gate, said first lever beingpivotally mounted on said second lever for adjustment to and from thepivotal axis of the gate and in a plane having lying therein saidpivotal axis, said gate having the upper edge thereof inclined outwardlyfrom the plane of the gate to increase the opening thrust on the gate insubstantial'opened positions thereof.

13. In a draft regulator, an open ended control housing for passage ofair therethrough to a flue, a control gate in said housing, said gatebeing mounted on a horizontal pivot to be opened by excess pressure onthe outer surface thereof,

counterweight means including a first lever to produce a closing torqueon said gate, a second lever pivotally mounted on said gate for angularadjustment to and from the plane of the gate. said first lever beingpivotally mounted on said tion of said sec'ondlever with the gate, saidgate having the upper edge portion thereof inclined outwardly from theplane of the gate to increase the opening thrust thereon in substantialopened positions thereof.

14. In a draft regulator device, comprising a cylindrical open-endedcontrol housing and a control gate of generally circular outline pivotedtherein on a'horizontal axis located adjacent the longitudinal center ofthe housing, the lateral and upper portion of the periphery of said gatebeing disposed closely adjacent said housing and the gate beingtruncated on a chord parallel to the gate axis to thereby afford a largepressure area differential on opposite vertical sides of said axis whileenabling the latter to be disposed adiacent the center of the frame andthe gate periphery closely adjacent the housing, a counterweight on saidgate to produce a closing torque on the same, and a stop to limit theopening movement of the gate when the plane of the gate is inclinedslightly upwardly-toward the rear, a first means for adjustablyretaining said counterweight means in a first position at a substantialdistance from the plane of the gate to adapt the draft regulator forconnection to a horizontal flue and in a second position at a greaterdistance from the plane of the gate to adapt the draft regulator forconnection to a vertical flue, said positions being disposed in the arcof a circle, the plane of the circle being substantially at right anglesto the plane of the gate and the center of the circle coincidingsubstantially with the pivotal axis of the gate, a second meanssupported by said first means for adjustably retainingsaid'counterweight means in positions at different distances from thepivotal axis of the gate, said positions last mentioned being disposedin a plane substantially coinciding with the pivotal axis of the gate,said gate having an upper portion thereof inclined outwardly from theplane of the gate to increase the opening thrust on the gate inrelatively widely opened positions thereof to supplement the decreasingclosing torque on said gate due to inward ovement of the center ofgravity of said cou terweight so as to cause the gate to open morewidely and thus acting to maintain -the draft at a more uniform value.

15. In a draft regulator, a cylindrical openended control housing forpassage of air therethrough to a fiue, a control gate of a generallycircular outline in said housing, said gate being mounted on ahorizontal pivot closely ad- Jacent the center of the housing for theupper portion of the gate to open inwardly by excess pressure on theouter surface thereof, counterweight means on said gate for producingclosing torque on said gate, the center of gravity of said counterweightmeans being disposed forwardly of the plane of the gate and below thehorizontal plane of the pivotal axis of the gate when the gate is in avertically closed position. said center of gravity being disposed tomove upwardly during the entire opening movement of said gate, and tomove a substantial distance inwardly during the latter portion of therelatively widely opened positions of the gate, said gate having aportion thereof adjacent the upper edge thereof inclined outwardly fromthe plane of the gate to increase the opening thrust on the gate duringsaid widely opened positions thereof to supplement the decreasingclosing torque on said gate caused by said inward movement of the centerof gravity of the counterweight during said-relatively wide openedpositions of the gate so as to cause the gate to open more widely andthus acting to maintain the draft at a more uniform value.

16. In a draft regulator, a cylindrical openended control housing, acontrol gate of generally circular outline adjacent the outer end ofsaid housing, said gate being vertically disposed in the closed positionthereof,'said gate being horizontally pivotally mounted adjacent thecenter of said housing for inward movement of the upper portion of thegate by excess pressure on the outer surface thereof, a stop forlimiting the inward movement of said upper portion of the gate when theplane of the gate is inclined slightly upwardly toward the rear, and acounterweight on said gate for producing closing torque on the same, thecenter of gravity of the counterweight being substantially spaced fromthe plane of the gate and beneath the horizontal plane of the pivotalaxis when the gate is in a vertical closed position, said center ofgravity being disposed substantially above said horizontal plane in thewidely opened position of the gate against said stop, a first means foradjustably retaining said counterweight means in a first position at asubstantial distance from the plane of the gate to adapt the draftregulator for connection to a horizontal flue and in a second positionat a greater distance from the plane of the gate to adapt the draftregulator for connection to a vertical flue, said positions beingdisposed in the arc of a circle, the plane of the circle beingsubstantially at right angles to the plane of the gate and the center ofthe circle coinciding substantially with the pivotal axis of the gate, asecond means supported by said first means for adjustably retaining saidcounterweight means in positions at different distances from the pivotalaxis of the gate, said positions last mentioned being disposed in aplane substantially coinciding with the pivotal axis of the gate, anupper portion of the gate being inclined outwardly relative to the planeof the gate to increase the opening thrust on the gate in widely openedpositions of the gate to supplement decreasing torque on said gate so asto cause the gate to open more widely and thus acting to maintain thedraft at a more uniform value.

17. In a draft regulator, an open-ended control housing, a control gatein the outer end of the housing, said gate being vertically disposed inthe closed position thereof, said gate being horizontally pivotallymounted for inward movement of the upper portion thereof by excess ofpressure on the outer surface thereof, a stop for limiting inwardmovement of the upper portion of the gate when the plane of the gate isinclined slightly upwardly toward the rear, and a counterweight on saidgate to produce a closing torque on the same, said counterweight beingdisposed to move upwardly and inwardly during the relatively widelyopened positions of the gate, a firstmeans for adjustably retaining saidcounterweight means in a first position at a substantial distance fromthe plane of the gate to adapt the draft regulator for connection. to ahorizontal flue and in a second position at a greater distance from theplane oi! the gate to adapt the draft regulator for connection to avertical flue, said positions being disposed in the arc of a circle, theplane of the circle being substantialLv at right angles to the plane ofthe gate and the center of the circle coinciding substantially with thepivotal axis of the gate, a second means supported by said first meansfor adjustably retaining said counterweight means in positions atdiflerent distances from the pivotal axis of the gate, said positionslast mentioned being disposed in a plane substantially coinciding withthe pivotal axis of the gate, an upper portion of the gate beinginclined outwardly from the plane of the gate to increase the openingthust onthe same during the relaitvely widely opened posltionstosupplement the decreasin closing torque on the gate so as to cause thegate to'open more widely and thus acting to maintain the draft at a moreuniform value.

EDWARD A. FIELD, JR.

14 REFERENCE-S CITED The following references are 01' record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 591,317 Alden Oct. 5, 18971,783,418 Field et a1. Dec. 2, 1930 0 1,848,850 Sturgis Mar. 8, 19322,004,948 Irsch June 18, 1935 2,182,625 Field Dec. 5, 1939 2,269,932Field -Jan. 13, 1942 2,346,740 Field Apr. 18, 1944 FOREIGN PATENTSNumber Country Date 212,306 Germany July 28, 1909

